Apparatus for controlled cooling of metal stock



Aug. 13, 1968 c. w. RITTERHOFF ET AL 3,396,534

. APPARATUS FOR CONTROLLED COOLING OF METAL STOCK Filed Nov. 29, 1965 Ik/IJ www L, E

.......1 Irl- E United States Patent O 3,396,564 APPARATUS FOR CONTROLLED COOL'NG F METAL STOCK n Charles W. Ritterhof and Robert D. Romer-il, Michigan City, Ind., assignors to Bethlehem Steel Corporation, a a corporation of Delaware `iled Nov. 29, 1965, Ser. No. 510,314 3 Claims. (Cl. 72-201) ABSTRACT 0F THE DISCLOSURE An apparatus for the controlled cooling of plate steel prior to iinish rolling thereof comprising an offset roller table and automatic means for transferring the plates to and from said table.

This invention relates in general to apparatus for rolling plate steel and more particularly to apparatus for controlling the finishing temperatures of the plate.

In the rolling of plate steel, particularly the alloy grades, it is desirable to carefully control the temperature of the unfinished plate prior to entry into the finishing mill. The close control of finishing temperature assures improved impact strength as a result of finer grain size and lower impact transition temperature. Cooling beds for cooling plate steel after rolling are well known and a familiar sight in rolling mills. However, suitable means for controlled cooling before the finishing mill without a loss in production was unknown before the instant invention. Present day requirements for quality rolled products and production schedules dictate a need for controlled cooling without slowing down the output from the mill.

It is therefore an object of this invention to provide means whereby the temperature of plates can be carefully controlled prior to finish rolling thereof.

It is a further object of this invention to provide means whereby the rolling mill can continue to roll while selected plates are being cooled.

Other objects and advantages will become apparent from the following description taken in `conjunction with the accompanying drawing in which the figure depicts one embodiment of the instant invention.

The present invention comprises generally rolling mill apparatus adapted to intermittent or continuous rolling by providing an offset temperature controlling means which bypasses the otherwise direct line of travel for plates discharged from the roughing mill before entry into the finishing mill.

Referring now in detail to the drawing, the temperature controlling means of the present invention is seen to comprise a lirst mill stand 1G or roughing mill, a second mill stand 11 or finishing mill, a roller table 12 disposed between and in longitudinal alignment with said first mill stand and said second mill stand 11 and temperature controlling means 13. Side guides 14 are provided at both the entry side and delivery side of each of said mill stands 10 and 11 for squaring and centering the workpiece and holding said piece during the rolling operation. In the pictured embodiment the roller table 12 is seen to comprise a rougher delivery table 15, approach table 16, approach table 17, approach table 18 and finishing mill entry table 19. The tables are all individually driven and reversible, lending considerable fiexibility to the operation. In addition, approach table 16 is adapted to oscillate the plates back and forth for reasons that will be described later.

Standard plates or plates not requiring controlled cooling may be passed directly through the mill by means of roller table 12, while special or quality steel plates are being control-cooled. Furthermore, plates may be linish ice rolled and then brought back for cooling, after finishing, on cooling beds 24 and 25 if desired.

Transfer chains 20 and 21, first and second conveying means respectively, are of the chain and dog type and and provided to transfer plates to and from the temperature controlling means 13. The transfer chains are mounted in trough members 22 and alternate with skid members 23. Trough members 22 and skid members 23 are both mounted on water cooled beams. The transfer chains 20 and 21 are reversible.

A second roller table 13 comprises two separately operable roller groups or cooling beds 24 and 25 which are disposed in longitudinal alignment substantially parallel to roller table 12 and offset therefrom a convenient distance, and said second roller table is provided with cooling means. Roller groups or cooling beds 24 and 25 are individually driven, reversible, and are adapted to oscillate the plates resting thereon so that said plates will be cooled uniformly avoiding marking of the plates and cold spots from the supporting rolls. The cooling means includes a cooling hood 27 covering a portion of cooling beds 24 and 25 and in which spray headers (not shown) are mounted above and below said cooling beds for the purpose of applying a coolant to the surfaces of the plate thus speeding up the rate of cooling. Spray headers are arranged in banks in order to vary the amount of coolant used at the discretion of the operator. Another embodiment (not shown) provides for the cooling hood to be removed completely and controlled cooling to take place in the air.

Automatic operation of the apparatus is accomplished by the provision of hot metal detecting means located as shown on the drawing as follows: hot metal detectors 28 and 29 at approach table 16, hot metal detectors 30 and 31 at cooling bed 24, hot metal detectors 32, 33 and 34 at cooling bed 25. Temperature pyrorneters 26 are located at cooling bed 25, approach table 18, and finishing mill entry table 19 for the information of the finishing mill operator to assure close control of the finishing mill rolling temperature.

The actual rolling procedure at the roughing mill, Whether manual, semi-automatic or automatic reversal, is the same for all types of steel. The roughing mill, with uted rolls, breaks the scale from the slab, makes the width of the finished plate and cross rolls the slab for added steel quality and improved surface cleanliness. However, for controlled cooling the particular cooling cycle or mode must be selected at the roughing mill. There are three phases in the cooling cycle, (l) approach table 16, (2) cooling bed 24 and (3) cooling bed 25. The plates move automatically through these three positions, with each unfinished plate Imoving to the next position when the plate in front vacates the position. The unfinished plate upon reaching the approach table 16 is slowed down by hot metal detector 28 and is stopped by hot metal detector 29. lf there is an unfinished plate already at cooling bed 24 the plate will oscillate between hot metal detectors 2S and 29. lf there is no plate at cooling bed 24, then transfer chain 2t) is started automatically, and the plate is moved to cooling bed 24. When the unnished plate reaches cooling bed 24 there is a time delay before the cooling bed starts operating, in which time transfer chain 26 reverses approximately two feet. This time delay is from one to five seconds and allows the transfer dogs to retract from the plate before it starts moving. lf there is an unfinished plate already on cooling ybed 25 the plate will oscillate 4between hot metal detectors 3) and 31. If there is no plate on cooling bed 25 then the plate will move thereon and when the plate reaches cooling bed 25 it will be slowed down when the front end covers hot metal detector 32. When the front end covers hot metal detector 33, the table will reverse, and the plate will oscillate between hot metal detector 32 and hot metal detector 33. During the time the plate is at cooling bed 24 or 25 a coolant may be applied as desired through the spray headers mounted within the cooling hood 27. The time of oscillation and the amount of coolant applied will depend on the temperature of the plate. To stop the oscillation at a predetermined temperature the release pushbutton, located in the finishing mill pulpit, is depressed. The unfinished, but properly cooled plate, then moves forward to hot metal detector 34 whereupon transfer chain 21 will automatically move the plate to approach table i8. The transfer chain is reversed and a time delay is applied before the approach table moves the plate toward the finishing mill stand, to complete the rolling operation.

It is readily apparent that the invention hereinbefore described is capable of `considerable fiexibility and lends itself to the continuous operation of the mill while providing for the controlled cooling of selected plates. Quality plates are carefully cooled to proper rolling temperatures without interfering with tight production schedules. The by-pass table arrangement allows continuous and reduced temperature rolling simultaneously.

Although reference is made throughout the description to cooling of plates it should be understood that the invention is equally adaptable to means of heating of plates. It should be understood further that the invention is equally adaptable to other rolled shapes as well.

We claim:

1. In a plate rolling mill including a first mill stand, a second mill stand, a first roller table in longitudinal alignment therebetween, the improvement comprising:

(a) a second roller table parallel to and laterally offset from said first roller table and having an entry end and a discharge end,

(b) first conveying means to transfer a plate from said first roller table to the entry end of said second roller table,

(c) second conveying means to transfer a plate from the discharge end of said second roller table to said first roller table,

(d) actuating means for said first conveying means,

(e) first automatic means to prevent the actuation of said actuating means when a plate is positioned at the entry end of said second roller table,

(f) second automatic means for oscillating the plate during the operation of said first automatic means. 2. Apparatus according to claim 1 further including: (g) third automatic means to actuate said second roller table.

3. In a plate rolling mill including a first mill stand, a second mill stand, a first roller table in longitudinal alignment therebetween, the improvement comprising:

(a) a second roller table parallel to and laterally offset from said first roller table and having an entry end and a discharge end,

(b) first conveying means t0 transfer a plate from said first roller table to the entry end of said second roller table,

(c) second conveying means to transfer a plate from the discharge end of said second roller table to said first roller table,

(d) actuating means for said first conveying means,

(e) automatic means to prevent the actuation of said actuating means when a plate is positioned at the entry end of said second roller table.

References Cited UNITED STATES PATENTS 1,555,919 10/1925 George et al 72-218 1,966,554 7/1934 Lee 72-40 FOREIGN PATENTS 756,259 9/1956 Great Britain.

CHARLES W. LANHAM, Primary Examiner.

H. DIETER HOINKES, Assistant Examiner. 

